KVM: Update halt polling documentation to note that KVM has 4 module params

KVM: Update halt polling documentation to note that KVM has 4 module params

Update KVM's halt-polling documentation to correclty reflect that KVM has
4 relevant module params, not 3 params.

Co-developed-by: Rajendran Jaishankar <jaishankar.rajendran@intel.com>
Signed-off-by: Rajendran Jaishankar <jaishankar.rajendran@intel.com>
Signed-off-by: Parshuram Sangle <parshuram.sangle@intel.com>
Link: https://lore.kernel.org/r/20231102154628.2120-3-parshuram.sangle@intel.com
[sean: drop unrelated and misleading doc update]
Signed-off-by: Sean Christopherson <seanjc@google.com>